[PATCH 6/8] iio: light: Add support for Azoteq IQS621 ambient light sensor

[Jeff LaBundy <jeff@labundy.com>]

This patch adds support for the Azoteq IQS621 ambient light sensor,
capable of reporting intensity directly in units of lux.

Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
 drivers/iio/light/Kconfig      |  10 ++
 drivers/iio/light/Makefile     |   1 +
 drivers/iio/light/iqs621-als.c | 361 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 372 insertions(+)
 create mode 100644 drivers/iio/light/iqs621-als.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 4a1a883..aad26dc 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -162,6 +162,16 @@ config GP2AP020A00F
 	  To compile this driver as a module, choose M here: the
 	  module will be called gp2ap020a00f.
 
+config IQS621_ALS
+	tristate "Azoteq IQS621 ambient light sensor"
+	depends on MFD_IQS62X
+	help
+	  Say Y here if you want to build support for the Azoteq IQS621
+	  ambient light sensor.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called iqs621-als.
+
 config SENSORS_ISL29018
 	tristate "Intersil 29018 light and proximity sensor"
 	depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 00d1f9b..aa34358 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_IIO_CROS_EC_LIGHT_PROX) += cros_ec_light_prox.o
 obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o
 obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o
 obj-$(CONFIG_HID_SENSOR_PROX)	+= hid-sensor-prox.o
+obj-$(CONFIG_IQS621_ALS)	+= iqs621-als.o
 obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o
 obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
 obj-$(CONFIG_ISL29125)		+= isl29125.o
diff --git a/drivers/iio/light/iqs621-als.c b/drivers/iio/light/iqs621-als.c
new file mode 100644
index 0000000..92a6173
--- /dev/null
+++ b/drivers/iio/light/iqs621-als.c
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Azoteq IQS621 Ambient Light Sensor
+ *
+ * Copyright (C) 2019
+ * Author: Jeff LaBundy <jeff@labundy.com>
+ */
+
+#include <linux/device.h>
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/kernel.h>
+#include <linux/mfd/iqs62x.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define IQS621_ALS_FLAGS			0x16
+#define IQS621_ALS_FLAGS_LIGHT			BIT(7)
+
+#define IQS621_ALS_UI_OUT			0x17
+
+#define IQS621_ALS_THRESH_DARK			0x80
+#define IQS621_ALS_THRESH_DARK_MAX		1020
+#define IQS621_ALS_THRESH_DARK_SHIFT		2
+
+#define IQS621_ALS_THRESH_LIGHT			0x81
+#define IQS621_ALS_THRESH_LIGHT_MAX		4080
+#define IQS621_ALS_THRESH_LIGHT_SHIFT		4
+
+struct iqs621_als_private {
+	struct iqs62x_core *iqs62x;
+	struct notifier_block notifier;
+	struct mutex lock;
+	bool event_en;
+	u8 thresh_light;
+	u8 thresh_dark;
+	u8 flags;
+};
+
+static int iqs621_als_init(struct iqs621_als_private *iqs621_als)
+{
+	struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+	unsigned int val;
+	int error;
+
+	mutex_lock(&iqs621_als->lock);
+
+	error = regmap_write(iqs62x->map, IQS621_ALS_THRESH_LIGHT,
+			     iqs621_als->thresh_light);
+	if (error)
+		goto err_mutex;
+
+	error = regmap_write(iqs62x->map, IQS621_ALS_THRESH_DARK,
+			     iqs621_als->thresh_dark);
+	if (error)
+		goto err_mutex;
+
+	error = regmap_read(iqs62x->map, IQS621_ALS_FLAGS, &val);
+	if (error)
+		goto err_mutex;
+	iqs621_als->flags = val;
+
+	error = regmap_update_bits(iqs62x->map, IQS620_GLBL_EVENT_MASK,
+				   iqs62x->dev_desc->als_mask,
+				   iqs621_als->event_en ? 0 : 0xFF);
+
+err_mutex:
+	mutex_unlock(&iqs621_als->lock);
+
+	return error;
+}
+
+static int iqs621_als_notifier(struct notifier_block *notifier,
+			       unsigned long event_flags, void *context)
+{
+	struct iqs62x_event_data *event_data = context;
+	struct iqs621_als_private *iqs621_als;
+	struct iio_dev *indio_dev;
+	enum iio_event_direction dir;
+	int error;
+
+	iqs621_als = container_of(notifier, struct iqs621_als_private,
+				  notifier);
+	indio_dev = iio_priv_to_dev(iqs621_als);
+
+	if (event_flags & BIT(IQS62X_EVENT_SYS_RESET)) {
+		error = iqs621_als_init(iqs621_als);
+		if (error) {
+			dev_err(indio_dev->dev.parent,
+				"Failed to re-initialize device: %d\n", error);
+			return NOTIFY_BAD;
+		}
+
+		return NOTIFY_OK;
+	}
+
+	if (!((event_data->als_flags ^ iqs621_als->flags) &
+	    IQS621_ALS_FLAGS_LIGHT))
+		return NOTIFY_DONE;
+
+	iqs621_als->flags = event_data->als_flags;
+
+	if (!iqs621_als->event_en)
+		return NOTIFY_OK;
+
+	dir = iqs621_als->flags & IQS621_ALS_FLAGS_LIGHT ? IIO_EV_DIR_RISING :
+							   IIO_EV_DIR_FALLING;
+
+	iio_push_event(indio_dev,
+		       IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
+					    IIO_EV_TYPE_THRESH, dir),
+		       iio_get_time_ns(indio_dev));
+
+	return NOTIFY_OK;
+}
+
+static void iqs621_als_notifier_unregister(void *context)
+{
+	struct iqs621_als_private *iqs621_als = context;
+	struct iio_dev *indio_dev = iio_priv_to_dev(iqs621_als);
+	int error;
+
+	error = blocking_notifier_chain_unregister(&iqs621_als->iqs62x->nh,
+						   &iqs621_als->notifier);
+	if (error)
+		dev_err(indio_dev->dev.parent,
+			"Failed to unregister notifier: %d\n", error);
+}
+
+static int iqs621_als_read_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int *val, int *val2, long mask)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+	struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+	int error;
+	__le16 val_buf;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		error = regmap_raw_read(iqs62x->map, IQS621_ALS_UI_OUT,
+					&val_buf, sizeof(val_buf));
+		if (error)
+			return error;
+
+		*val = le16_to_cpu(val_buf);
+		return IIO_VAL_INT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int iqs621_als_read_event_config(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan,
+					enum iio_event_type type,
+					enum iio_event_direction dir)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+
+	return iqs621_als->event_en;
+}
+
+static int iqs621_als_write_event_config(struct iio_dev *indio_dev,
+					 const struct iio_chan_spec *chan,
+					 enum iio_event_type type,
+					 enum iio_event_direction dir,
+					 int state)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+	struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+	int error;
+
+	mutex_lock(&iqs621_als->lock);
+
+	error = regmap_update_bits(iqs62x->map, IQS620_GLBL_EVENT_MASK,
+				   iqs62x->dev_desc->als_mask,
+				   state ? 0 : 0xFF);
+	if (!error)
+		iqs621_als->event_en = state;
+
+	mutex_unlock(&iqs621_als->lock);
+
+	return error;
+}
+
+static int iqs621_als_read_event_value(struct iio_dev *indio_dev,
+				       const struct iio_chan_spec *chan,
+				       enum iio_event_type type,
+				       enum iio_event_direction dir,
+				       enum iio_event_info info,
+				       int *val, int *val2)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+
+	switch (dir) {
+	case IIO_EV_DIR_RISING:
+		*val = iqs621_als->thresh_light;
+		*val <<= IQS621_ALS_THRESH_LIGHT_SHIFT;
+		return IIO_VAL_INT;
+
+	case IIO_EV_DIR_FALLING:
+		*val = iqs621_als->thresh_dark;
+		*val <<= IQS621_ALS_THRESH_DARK_SHIFT;
+		return IIO_VAL_INT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int iqs621_als_write_event_value(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan,
+					enum iio_event_type type,
+					enum iio_event_direction dir,
+					enum iio_event_info info,
+					int val, int val2)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+	struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+	int error = -EINVAL;
+
+	mutex_lock(&iqs621_als->lock);
+
+	switch (dir) {
+	case IIO_EV_DIR_RISING:
+		if (val > IQS621_ALS_THRESH_LIGHT_MAX)
+			break;
+		val >>= IQS621_ALS_THRESH_LIGHT_SHIFT;
+
+		error = regmap_write(iqs62x->map, IQS621_ALS_THRESH_LIGHT, val);
+		if (!error)
+			iqs621_als->thresh_light = val;
+		break;
+
+	case IIO_EV_DIR_FALLING:
+		if (val > IQS621_ALS_THRESH_DARK)
+			break;
+		val >>= IQS621_ALS_THRESH_DARK_SHIFT;
+
+		error = regmap_write(iqs62x->map, IQS621_ALS_THRESH_DARK, val);
+		if (!error)
+			iqs621_als->thresh_dark = val;
+		break;
+
+	default:
+		break;
+	}
+
+	mutex_unlock(&iqs621_als->lock);
+
+	return error;
+}
+
+static const struct iio_info iqs621_als_info = {
+	.read_raw = &iqs621_als_read_raw,
+	.read_event_config = iqs621_als_read_event_config,
+	.write_event_config = iqs621_als_write_event_config,
+	.read_event_value = iqs621_als_read_event_value,
+	.write_event_value = iqs621_als_write_event_value,
+};
+
+static const struct iio_event_spec iqs621_als_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+	},
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE),
+	},
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE),
+	},
+};
+
+static const struct iio_chan_spec iqs621_als_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.event_spec = iqs621_als_events,
+		.num_event_specs = ARRAY_SIZE(iqs621_als_events),
+	},
+};
+
+static int iqs621_als_probe(struct platform_device *pdev)
+{
+	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
+	struct iqs621_als_private *iqs621_als;
+	struct iio_dev *indio_dev;
+	unsigned int val;
+	int error;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*iqs621_als));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->channels = iqs621_als_channels;
+	indio_dev->num_channels = ARRAY_SIZE(iqs621_als_channels);
+	indio_dev->name = iqs62x->dev_desc->dev_name;
+	indio_dev->info = &iqs621_als_info;
+
+	iqs621_als = iio_priv(indio_dev);
+	iqs621_als->iqs62x = iqs62x;
+
+	error = regmap_read(iqs62x->map, IQS621_ALS_THRESH_LIGHT, &val);
+	if (error)
+		return error;
+	iqs621_als->thresh_light = val;
+
+	error = regmap_read(iqs62x->map, IQS621_ALS_THRESH_DARK, &val);
+	if (error)
+		return error;
+	iqs621_als->thresh_dark = val;
+
+	mutex_init(&iqs621_als->lock);
+
+	error = iqs621_als_init(iqs621_als);
+	if (error)
+		return error;
+
+	iqs621_als->notifier.notifier_call = iqs621_als_notifier;
+	error = blocking_notifier_chain_register(&iqs621_als->iqs62x->nh,
+						 &iqs621_als->notifier);
+	if (error) {
+		dev_err(&pdev->dev, "Failed to register notifier: %d\n", error);
+		return error;
+	}
+
+	error = devm_add_action_or_reset(&pdev->dev,
+					 iqs621_als_notifier_unregister,
+					 iqs621_als);
+	if (error) {
+		dev_err(&pdev->dev, "Failed to add action: %d\n", error);
+		return error;
+	}
+
+	return devm_iio_device_register(&pdev->dev, indio_dev);
+}
+
+static struct platform_driver iqs621_als_platform_driver = {
+	.driver = {
+		.name	= IQS621_DRV_NAME_ALS,
+	},
+	.probe		= iqs621_als_probe,
+};
+module_platform_driver(iqs621_als_platform_driver);
+
+MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
+MODULE_DESCRIPTION("Azoteq IQS621 Ambient Light Sensor");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" IQS621_DRV_NAME_ALS);
-- 
2.7.4